I was sick of running out of Battery with my Iphone 6s, so i picked up this case with a battery in it from apple. It does not add much weight at all but it make the battery life insanely long. I no longer have to keep looking where to charge up my phone!
Where to Buy?
http://www.apple.com/shop/product/MGQM2LL/A/iphone-6s-smart-battery-case-white
more info at:
http://Reviewoutlaw.com